ROS2 gazebo (classic) LIDAR sensor

#gazebo   #ros2   #sensors   #ray   #gazebo_ros_ray_sensor   #lidar   #ultrsonic   #range  

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Table of Content

ROS2 gazebo (classic) LIDAR sensor

ROS2 using new plug gazebo_ros_ray_sensor to simulate PointCloud, LaserScan and Range output message control by <output_type> tag

• sensor_msgs/PointCloud2: 3D cloud of points (default)
• sensor_msgs/PointCloud: 3D cloud of points
• sensor_msgs/LaserScan: 2D scan, uses center vertical ray if there are multiple
• sensor_msgs/Range: Single distance value, minimum of all ray ranges of parent sensor

Demo

SDF

<?xml version="1.0"?>
<sdf version="1.5">
    <model name="lidar_demo">
        <pose>0 0 0.5 0 0 0</pose>
        <static>true</static>
        <link name="link">
            <collision name="collision">
                <geometry>
                    <box>
                        <size>0.1 0.1 0.1</size>
                    </box>
                </geometry>
            </collision>
            <visual name="visual">
                <geometry>
                    <box>
                        <size>0.1 0.1 0.1</size>
                    </box>
                </geometry>
            </visual>
            <sensor name="lidar" type="ray">
                <always_on>true</always_on>
                <visualize>true</visualize>
                <update_rate>5</update_rate>
                <ray>
                  <scan>
                    <horizontal>
                      <samples>180</samples>
                      <resolution>1.00000</resolution>
                      <min_angle>-1.57</min_angle>
                      <max_angle>1.57</max_angle>
                    </horizontal>
                  </scan>
                  <range>
                    <min>0.5</min>
                    <max>3.5</max>
                    <resolution>0.1</resolution>
                  </range>
                </ray>
                <plugin name="scan" filename="libgazebo_ros_ray_sensor.so">
                  <ros>
                    <remapping>~/out:=scan</remapping>
                  </ros>
                  <output_type>sensor_msgs/LaserScan</output_type>
                  <frame_name>link</frame_name>
                </plugin>
              </sensor>
        </link>
    </model>
</sdf>

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Run

sensor_msgs/Range

<plugin name="ultrasonic_sensor" filename="libgazebo_ros_ray_sensor.so">
    <ros>
        <remapping>~/out:=range</remapping>
    </ros>
    <output_type>sensor_msgs/Range</output_type>
    <frame_name>link</frame_name>
</plugin>

ros2 topic info /range
#
Type: sensor_msgs/msg/Range
Publisher count: 1

header:
  stamp:
    sec: 2978
    nanosec: 715000000
  frame_id: link
radiation_type: 1
field_of_view: 0.23999999463558197
min_range: 0.5
max_range: 2.5
range: 2.013324022293091

This type of message raise exception when reading is out of range

ros2 topic echo /range 
#
Unable to convert call argument to Python object (compile in debug mode for details)

I Open an issue for this exception

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sensor_msgs/LaserScan

<plugin name="ultrasonic_sensor" filename="libgazebo_ros_ray_sensor.so">
    <output_type>sensor_msgs/LaserScan</output_type>
    <frame_name>link</frame_name>
</plugin>

ros2 topic info /ultrasonic_sensor/out
# 
Type: sensor_msgs/msg/LaserScan

header:
  stamp:
    sec: 109
    nanosec: 415000000
  frame_id: link
angle_min: -0.11999999731779099
angle_max: 0.11999999731779099
angle_increment: 0.05999999865889549
time_increment: 0.0
scan_time: 0.0
range_min: 0.5
range_max: 2.5
ranges:
- .inf
- 1.8191075325012207
- 1.7666829824447632
- 1.8185886144638062
- .inf
intensities:
- 0.0
- 0.0
- 0.0
- 0.0
- 0.0

.inf

When a beam is out of range (min/max) it’s return .inf

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Reference

• ROS 2 Migration: Ray sensors